1. Field of the Invention
The present invention pertains to apparatus for use with internal combustion engines for reducing noise, noxious components of exhaust gases emitted therefrom and recovering heat from the exhaust gases thereof. More specifically, the present invention pertains to apparatus, mounted in a single housing, which provides combined functions of noise silencing, reduction of noxious gas components and recovery of useable heat from the exhaust of an internal combustion engine, particularly naturally gas-fueled engines.
2. Brief Description of the Prior Art
Silencers or mufflers for internal combustion engines have been in existence for many years. Most industrial silencers use some type of shell or housing in which is mounted various types of baffles for reducing noise produced at the exhaust of an internal combustion engine. In recent years, attention has also been directed to reducing the noxious gases emitted in the exhaust of an internal combustion engine, e.g. nitrogen oxide, carbon monoxide and other unburned hydrocarbons. Equipment for reducing noxious emissions from internal combustion engines usually provide some type of catalyst which converts gases to water, nitrogen, carbon dioxide and other harmless emissions.
Most exhaust emission control apparatus, particularly those for silencing and reducing the noxious emissions of internal combustion engines in industrial applications utilize separate devices for noise reduction and noxious gas reduction. In recent years, apparatus has been provided which has the combined function of noise and emission control in a single enclosed housing. Examples of such are shown in U.S. Pat. Nos. 4,209,493 and 4,601,168.
Some of the heat of combustion of an internal combustion engine is usually dissipated to a cooling fluid which circulates through the engine and then releases heat to the atmosphere through a radiator. Additional heat energy is lost to the atmosphere through escaping hot gases. In many cases, it would be desirable to recover and utilize the heat energy from the heat of combustion of the engine and the heat of recombustion of a catalytic muffler. Some attempts have been made to recover heat energy from exhaust gases. U.S. Pat. No. 4,777,796 discloses a muffler system which recovers heat energy of exhaust gases by spraying a fluid into the exhaust stream to absorb the heat energy, collecting the heated fluid at the bottom of the muffler vessel and transferring heat to a second fluid via a counter-current liquid-to-liquid heat exchanger. A combination catalytic muffler and heat recovery system is also disclosed in U.S. Pat. No. 4,426,844. However, this system, designed primarily for a two-cycle engine driven refrigerant compressor of a room cooling system would probably be inadequate for a large industrial internal combustion engine.